Aluminum beverage cans are produced in vast quantities. Conventional beverage cans include a one-piece, drawn and ironed body and an end that is attached to a flange of the can body by a double seam. A can end, in its unseamed state, has a peripheral curl for seaming to the can body flange, a wall extending from the curl (that is, a chuck wall), an annular bead (that is, a countersink), or like structure extending from the wall and a center panel.
Conventional center panels have a score that defines a tear panel and a tab that is attached to the center panel by a rivet. The score has first and second ends that define a hinge about which the tear panel actuates. In the vast majority of commercial ends, the hinge is not centered relative to the score and tear panel, but rather is located to a side. The score extends from its first end in front of the rivet about a curved path to its second end. Conventional large opening ends (LOE) have an elongated opening.
Commercial ends of the LOE-type are opened only by lifting the heel of the tab to force the tab nose against the tear panel. The downward force initiates an initial venting, which is promoted by a check slot, and the downward force then displaces the tear panel and ruptures the remainder of the score to form an opening.
Pouring from conventional beverage cans creates unsteady state flow or “glugs,” as described in U.S. patent application Ser. No. 09/857,145, which is assigned to the assignee of the present invention.
U.S. Pat. Nos. 6,354,453; 6,079,583; 5,555,992; 5,011,037; and 3,977,561 disclose can ends that have been purported to create a vent after opening. There is a need for improved can end configurations that promote venting after opening of the tear panel.
Making a score in a metal sheet causes a phenomenon referred to as metal flow or slack metal. Slack metal is created when a tool impacts the sheet metal of a commercial beverage can end to create a score. The second score common to many commercial beverage can ends is known as an antifracture score, the purpose of which is to resist metal flow. A recess can reduce or take up slack metal. Other means for effecting slack metal are known.
A popular type of recess for 12 ounce beverage cans is known as a Stolle-type recess or a Stolle-type end, which has a pair of opposing rounded ends between tapering sides to give the appearance of a trapezoid having rounded opposing sides. In a Stolle-type end, the tab and tear panel are located within the recess.
Another popular center panel configuration, known as a DRT style end, does not have a recess that encompasses the tear panel and tab, but rather includes raised beads. Further, a typical DRT style center panel includes only a single score (that is, does not have an antifracture score). The single score of the DRT-style end typically has a different score profile (in transverse cross section) than a typical score profile of a Stolle-style main score. U.S. Patent publication US20130037542, which is incorporated herein, shows an embodiment of a DRT-style center panel.